linux 下串口接受问题
#include <stdio.h> /*标准输入输出定义*/
#include <stdlib.h> /*标准函数库定义*/
#include <unistd.h> /*Unix标准函数定义*/
#include <sys/types.h> /**/
#include <sys/stat.h> /**/
#include <fcntl.h> /*文件控制定义*/
#include <termios.h> /*PPSIX终端控制定义*/
#include <errno.h> /*错误号定义*/
#include <string.h>
#define _POSIX_SOURCE 1
#define FALSE 0
#define TRUE 1
/***@brief 设置串口通信速率
*@param fd 类型 int 打开串口的文件句柄
*@param speed 类型 int 串口速度
*@return void*/
int speed_arr[] = { B38400, B19200, B9600, B4800, B2400, B1200, B300,
B38400, B19200, B9600, B4800, B2400, B1200, B300, };
int name_arr[] = {38400, 19200, 9600, 4800, 2400, 1200, 300,
38400, 19200, 9600, 4800, 2400, 1200, 300, };
void set_speed(int fd, int speed)
{
int i;
int status;
struct termios Opt;
tcgetattr(fd, &Opt);
for ( i= 0; i < sizeof(speed_arr) / sizeof(int); i++)
{
if (speed == name_arr[i])
{
tcflush(fd, TCIOFLUSH);
cfsetispeed(&Opt, speed_arr[i]);
cfsetospeed(&Opt, speed_arr[i]);
status = tcsetattr(fd, TCSANOW, &Opt);
if (status != 0)
perror( "tcsetattr fd1 ");
return;
}
tcflush(fd,TCIOFLUSH);
}
}
/**
*@brief 设置串口数据位，停止位和效验位
*@param fd 类型 int 打开的串口文件句柄*
*@param databits 类型 int 数据位 取值 为 7 或者8*
*@param stopbits 类型 int 停止位 取值为 1 或者2*
*@param parity 类型 int 效验类型 取值为N,E,O,,S
*/
int set_Parity(int fd,int databits,int stopbits,int parity)
{
struct termios options;
if ( tcgetattr( fd,&options) != 0)
{
perror( "SetupSerial 1 ");
return(FALSE);
}
options.c_cflag &= ~CSIZE;
switch (databits) /*设置数据位数*/
{
case 7:
options.c_cflag |= CS7;
break;
case 8:
options.c_cflag |= CS8;
break;
default:
fprintf(stderr, "Unsupported data size\n ");
return (FALSE);
}
switch (parity)
{
case 'n ':
case 'N ':
options.c_cflag &= ~PARENB; /* Clear parity enable */
options.c_iflag &= ~INPCK; /* Enable parity checking */
break;
case 'o ':
case 'O ':
options.c_cflag |= (PARODD | PARENB); /* 设置为奇效验*/
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case 'e ':
case 'E ':
options.c_cflag |= PARENB; /* Enable parity */
options.c_cflag &= ~PARODD; /* 转换为偶效验*/
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case 'S ':
case 's ': /*as no parity*/
options.c_cflag &= ~PARENB;
options.c_cflag &= ~CSTOPB;
break;
default:
fprintf(stderr, "Unsupported parity\n ");
return (FALSE);
}
/* 设置停止位*/
switch (stopbits)
{
case 1:
options.c_cflag &= ~CSTOPB;
break;
case 2:
options.c_cflag |= CSTOPB;
break;
default:
fprintf(stderr, "Unsupported stop bits\n ");
return (FALSE);
}
/* Set input parity option */
if (parity != 'n ')
options.c_iflag |= INPCK;
options.c_lflag &=~(ICANON | ECHO | ECHOE | ISIG);//*********no back show
options.c_cc[VTIME] = 0; // 15 seconds
options.c_cc[VMIN] = 5;
//tcflush(fd,TCIFLUSH); /* Update the options and do it NOW */
if (tcsetattr(fd,TCSANOW,&options) != 0)
{
perror( "SetupSerial 3 ");
return (FALSE);
}
return (TRUE);
}
/**
*@breif 打开串口
*/
int OpenDev(char *Dev)
{
intfd = open( Dev, O_RDWR ); //| O_NOCTTY | O_NDELAY
if (-1 == fd)
{ /*设置数据位数*/
perror( "Can 't Open Serial Port ");
return -1;
}
else
return fd;
}
/**
*@breif main()
*/
int main(int argc, char **argv)
{
int fd;
int nread;
char buff[512];
char *dev = "/dev/ttyS0 ";
fd = OpenDev(dev);
if (fd> 0)
set_speed(fd,19200);
else
{
printf( "Can 't Open Serial Port!\n ");
exit(0);
}
if (set_Parity(fd,8,1, 'N ')== FALSE)
{
printf( "Set Parity Error\n ");
exit(1);
}
while(1)
{
nread = read(fd,buff,255);
if(nread> 0)
{
buff[nread]=0;
printf( "%d,%s\n ",nread,buff);
write(fd,buff,5);
}
}
close(fd);
exit(0);
}
这段代码源于网上，可以接受到数据，但不能发送
想实现数据接收后经过处理再发送出去，该怎么修改，请指教！！
[解决办法]
fd = open( dev, O_RDWR | O_NOCTTY );
